ABSTRACT
The changes of aromatase and 5α-reductase activities were studied in preoptic area (POA) and medial basal hypothalamus of 10-days-old and sexual behavior in 3-month-old male offsprings of rats exposed daily to noradrenaline antagonist methyldopa (400 mg/kg per os) 30 minutes prior to 1-hour immobilization during the last week of pregnancy (from 15th to 21st day). Prenatal stress caused aromatase activity lowering in the POA of developing brain and feminization (appearance of lordosis) and demasculinization of sexual behavior (prolongation of latent periods to the first mounting and first intromission as well as of the first ejaculation and postejaculation refractory period) in young male offspring. Oral methyldopa used prior to pregnant females stressing prevented early effect of prenatal stress on aromatase activity in the POA and normalized the male sexual behavior in young male rats by shortening both latent period to the first ejaculation and postejaculation refractory period, and an increase of numbers of ejaculation. The data obtained indicate that brain noradrenergic system plays significant role in the mechanisms of metabolic- and behavioral disturbances developing in male rats exposed to prenatal stress.
Subject(s)
Feminization/prevention & control , Hypothalamus/drug effects , Methyldopa/pharmacology , Prenatal Exposure Delayed Effects , Sexual Behavior, Animal/drug effects , Stress, Psychological/prevention & control , Visual Cortex/drug effects , 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/metabolism , Animals , Aromatase/metabolism , Copulation/drug effects , Ejaculation/drug effects , Female , Feminization/enzymology , Feminization/physiopathology , Gestational Age , Hypothalamus/enzymology , Hypothalamus/physiopathology , Immobilization , Male , Maternal Exposure , Pregnancy , Rats , Rats, Wistar , Stress, Psychological/enzymology , Stress, Psychological/physiopathology , Visual Cortex/enzymology , Visual Cortex/physiopathologyABSTRACT
Experiments on the Wistar rats showed that neonatal daily injections of phenobarbital (35 mg/kg) during first 3 days of life resulted in the enzyme imprinting of liver microsomal monooxygenases. Rise in the activities of liver microsomal oxidation enzymes is constantly maintained during all the life leading to increase in average lifespan of rats. Analysis of the survival curves in Gompertz equation co-ordinates showed that enzyme imprinting by phenobarbital caused changes in mortality patterns at different stages of ontogenesis. The phenomenon of enzyme imprinting by phenobarbital and lifespan prolongation was registered only in females but not in males. An inverse correlation was found between the duration of phenobarbital sleeping time and lifespan of rats.
